What was going on when I was born?

Members of the Organization of Petroleum Exporting Countries have apparently reached agreement on a last-ditch effort to prop up sagging oil prices and will hold a special meeting in two weeks to ratify it. In informal talks in Doha, Qatar, over the last two days, the group, which will meet again in Vienna on March 19, decided to cut production limits by more than a million barrels a day to stop the fall in open-market prices. ''Any observers who are expecting that prices will go down will find they have made a complete mistake,'' said Mana Said al-Oteiba, Oil Minister of the United Arab Emirates and the current president of the 13-nation OPEC group. Informal Talks by Arab Producers The consultations took place in Doha during a meeting of the Organization of Arab Oil Exporting Countries. This organization is made up of the seven Arab members of OPEC - Algeria, Iraq, Kuwait, Libya, Qatar, Saudi Arabia and United Arab Emirates - plus Bahrain and Syria, which do not belong to OPEC.

Victory in El Salvador, from the Reagan Administration's point of view, will take a lot more fighting there and a lot of explaining in Washington. Last week, despite stepped-up activity on both fronts, Reagan officials were claiming no big advances. One Presidential aide acknowledged ''the success of the El Salvador insurgents in the past couple of months.'' President Reagan was told that the guerrillas might succeed in disrupting March 28 elections, a crucial element of Administration strategy to gain legitimacy for a centrist government. Without explanation, the Salvadoran Army cut short a major offensive against guerrilla strongholds 20 miles from the capital.

Secretary of State Alexander M. Haig Jr. and Foreign Minister Jorge Castaneda of Mexico met in New York yesterday to discuss the situation in Central America. But they disagreed over the issue of Nicaraguan arms shipments to leftist insurgents in El Salvador. After the two-and-a-half-hour meeting, Mr. Haig told reporters that a failure to deal with the Nicaraguan concern was the principal weakness in the peace plan advanced last month by President Jose Lopez Portillo of Mexico. Mr. Castaneda described the current arms flow from Nicaragua to El Salvador as ''fairly small and unimportant.'' Halting it, he said, depends on United States concessions, among them a less belligerent attitude toward Nicaragua.

TRENTON THE state's Democrats were caught overreaching last week when a three-judge panel in Federal District Court here ruled, 2 to 1, that the Congressional districts designed by the last Legislature and signed into law by former Gov. Brendan T. Byrne were unconstitutional. In their zeal to gerrymander the Republicans almost out of existence, the Democrats, in the eyes of the court majority, did not do as well as they could have to design districts with nearly equal populations. Under the one-man, one-vote doctrine, the districts are supposed to contain the same number of residents. Period. Everyone recognizes that absolute equality is impossible, but that is the goal, and any deviation from that goal must be justified. Those in charge of drawing the maps - in this case, it was the Democrats in the Legislature - must prove that they made a ''good faith'' effort to include the same number of people in each district without going to the extreme of drawing a line through someone's bedroom.

IVORYTON THE wooden seats were a symbol - certainly of discomfort, and possibly of failure. But now, the director of the venerable Ivoryton Playhouse, in its heyday billed as Connecticut's ''first and oldest'' summer stock theater, says that the old chairs will be torn out and replaced by a new set of movie-theater type seats, their cushions upholstered in gray and blue. The mood in the theater now is vastly different than it has been. With its roof leaking, its shingles falling off and the paint on the letters of its name flaking, the playhouse was sold in 1973 by its founder, Milton Stiefel, who had owned and run it since 1930. Several men tried to manage the theater in Mr. Stiefel's style, with big names and Broadway shows, but they failed.

With the President toughing it out in the bully pulpit, the Adminstration's good soldiers were left to slog up Capitol Hill last week, defending the virtues of his economic program and explaining the vagaries of the economy. All in all, the going wasn't easy -or made any easier by the week's economic indicators. As budget director David A. Stockman was telling the Chamber of Commerce of the United States that business failures and record deficits were ending the ''curse of inflation,'' chief economic adviser Murray L. Weidenbaum was before the Senate Budget Committee backing away from his former firm prediction that the recession would end by spring. Federal Reserve Board chairman Paul A. Volcker met with more anxiety. ''There are risks,'' he told the Senate Banking Committee, but ''I wouldn't characterize them as (of) depression.''

ARECOMMENDATION by the NJ Transit staff that the state take over the operation of New Jersey's commuter railroad lines is generally being accepted as the most sensible way out of a tough situation. But many people - state and union officials, lawmakers and commuters alike - worry whether the state is up to the task of running a railroad. Late last month, the NJ Transit staff, along with a special rail committee of the agency's board of directors, proposed that NJ Transit take over direct operation of the commuter service after Conrail withdrew from that role at the end of the year. Although NJ Transit owns the trains and most of the track within the state, it contracts with Conrail to actually operate the trains. According to Carl Golden, Governor Kean's press secretary, the Governor agrees with the NJ Transit recommendation, but has some misgivings about it.

Five of the 24 Moslem fundamentalists accused of involvement in the assassination of President Anwar el-Sadat were sentenced to death today. Seventeen other defendants were also convicted and received prison terms ranging from one year to life. Two defendants were acquitted of direct involvement in the killing of Mr. Sadat, which took place as he viewed a military parade Oct. 6. The 100-day trial was held mostly in secret. Only the first two sessions and today's final session were open to the press and to relatives of the defendants. The trial took place before a threejudge military court in a heavily guarded military encampment not far from the parade field where Mr. Sadat was slain.

America's oldest permanent orchestra plays its 10,000th concert today. It has one name - the New York Philharmonic, but its personalities have been many. From the first appearance Dec. 7, 1842, at the Apollo Rooms on Lower Broadway to this afternoon's performance of the Mahler ''Resurrection'' Symphony under Zubin Mehta at Avery Fisher Hall, the Philharmonic has grown and solidified as an institution. Still - as the history of its recordings shows - its identity is elusive. This may be an orchestra of tough, sometimes contrary individuals; but listening to a cross-section of its recent recorded history on CBS and its reissue label, Odyssey, one is struck forcibly by the Philharmonic's ability to adapt its sound and its technique to any conductor with a personality strong enough to command its attention. How opposite to the venerable Vienna Philharmonic, also founded in 1842. The Vienna is rich in its own personal style, but - like the city itself - enveloped by its own endearing idiosyncracies, by old habits which fend off the rest of the world and its influences. The Vienna Philharmonic - with its unique warmth of string and brass playing - has a way of making conductors play as it wants them to. When the music is Bruckner or Mozart, this selfishness becomes a gift to us all. In music such as Stravinsky's or Webern's, the results are often less happy.

The other shoe is due to fall this week for Harrison A. Williams Jr., the Abscam inquiry's most prominent target. But there are those who favor letting him continue to serve as New Jersey's senior Senator. He and they have tried to make the conduct of his Government pursuers seem more reprehensible than his failure to walk away from temptation.

Last fall, Dominic Imprescia took a gamble. Timely Writer, the outstanding 2-year-old colt he trained, had won the Hopeful and Champagne Stakes and could have wrapped up the 2-year-old championship with another stakes victory. But Imprescia decided that his colt was tired and would be better as a 3-year-old if he were rested for the winter. Deputy Minister then won two lateseason stakes and was voted the championship. Today, Imprescia's gamble paid off. Starting from the 15th post, Timely Writer circled the field with one devastating burst to win the $250,000 Flamingo Stakes. Now, while Deputy Minister is sidelined through the summer with a wrenched ankle, Timely Writer is clearly the horse to beat in the Kentucky Derby May 1.

OH WHAT A PARADISE IT SEEMS By John Cheever. 100 pp. New York: Alfred A. Knopf. $10. By JOHN LEONARD AMONG the living, John Cheever's favorite American writer is Saul Bellow. It is as if the apple wanted to be a lemon, and can't. ''Oh What a Paradise It Seems,'' a very short and often lovely novel, might just as easily have been a long letter from Cheever to Bellow on being old. But what would Bellow's Mr. Sammler make of Cheever's Lemuel Sears? They seem not to be visiting the same planet. Lemuel - from the Hebrew: ''pledged'' or ''consecrated to God'' - forgives the planet in advance: ''Coming from a generation that could, perhaps, be characterized by the vastness of its disposition to complain, he didn't suppose he could scorn men and women who must be looking for something better. That things had been better was the music, the reprise for his days. It had been sung by his elders, by his associates, he had heard it sung in college by Toynbee and Spengler. ... What a bore it had been to live in this self-induced autumnal twilight!''