What was going on when I was born?

With both sides publicly claiming victory in the debate between Vice President Bush and Representative Geraldine A. Ferraro, the private assessment in both campaigns today was that the debate would probably cause little shift of support in the Presidential race. Both the Republican and the Democratic camps regarded the outcome as less clear-cut than that of last Sunday's Presidential debate. Several officials on each side suggested that each candidate had achieved a goal in the debate Thursday night and that the mixed results would quickly throw public focus back on the contest between President Reagan and Walter F. Mondale. Mondale Asks an Apology In Minneapolis, Mr. Mondale demanded an apology from Mr. Bush for saying in the debate that the Democrats had suggested that Americans killed in Lebanon ''died in shame.'' (Page 8.)

The 98th Congress faded into history at 3:17 o'clock this afternoon, ending a week of legislative snarls in wearying late- night sessions, as the Senate voted 37 to 30 to approve an increase in the debt limit. ''May I say to my colleagues that there will be no more votes today, there will be no more votes this session, there will be no more votes in my career,'' said the majority leader, Howard H. Baker Jr., Republican of Tennessee, who is retiring. His anouncement was greeted with prolonged applause, a breach of Senate rules. ''For one brief moment I thought that was for me,'' Mr. Baker responded, ''but I realize it's for adjournment.''

A subway car that burst into flame Thursday at the Borough Hall station in Brooklyn had been in and out of the repair shop dozens of times since July, the Transit Authority said yesterday. The car had serious electrical problems and should have been removed from service, the authority said. But instead, in apparent violation of new maintenance rules, it was returned to the tracks over and over again, with minor repairs that failed to solve the problems. The car, No. 9000, went back into service Thursday and completed half of its run before catching fire at 4:55 P.M., apparently when its switch box overheated. Two thousand passengers were removed from the train, and the flames burned out of control until the floor of the car melted.

President Jose Napoleon Duarte of El Salvador said today that his Government had rejected a request by guerrilla leaders that outside observers serve as intermediaries for their scheduled meeting on Monday. But Mr. Duarte said he believed the negotiations would nonetheless go forward. Mr. Duarte said in an interview that he had dismissed the rebel demand for outside intermediaries because he felt the issue of peace was primarily a national question. ''For this I have proposed the meeting in La Palma in Salvadoran territory, with the Salvadorans, to seek a solution to the problems of Salvadorans,'' he said. Would Be First Such Talks It was not clear whether the Government's response to the rebel request would imperil the meeting, which Mr. Duarte proposed. Only two days remain to settle final details of the first face-to-face discussion between Government and rebel cfficials inside El Salvador.

The Irish Republican Army took responsibility today for planting a bomb in a seafront hotel that killed at least two people, wounded at least 34 and came within minutes of killing or maiming Prime Minister Margaret Thatcher. Mrs. Thatcher, who escaped without injury, had just left the bathroom of her second-floor suite to return to work on her speech for the concluding session of the annual Conservative Party conference when the explosion ripped through the Grand Hotel early today. Her husband, Denis, later reported that the bathroom was ''mangled.'' Cabinet Member Trapped Norman Tebbit, the Minister of Trade and Industry, plunged two stories when floors collapsed and spent four hours buried beneath rubble before firemen cut him free. He suffered broken ribs and a gashed thigh but no internal injuries. Mr. Tebbit is a senior figure in the Government and a candidate to succeed the Prime Minister.

Producer prices for finished goods fell two-tenths of 1 percent in September, held down by declines in the cost of food and fuel, the Labor Department reported today. The size of the decline in the Producer Price Index surprised some economists. The index, which measures changes in prices that industry charges retailers, has shown more rises than declines in the last several years, and no decline in the previous 21 months had been as large as September's. The September decline followed a drop of one-tenth of 1 percent in August. The back-to-back declines are the first in eight years. They may help to relieve worries that inflation is accelerating, worries that were fueled by last month's report of a spurt of five-tenths of 1 percent in the Consumer Price Index.

Walter Byers, the executive director of the National Collegiate Athletic Association, says that illegal payments and other improprieties are so widespread in intercollegiate athletics that a convention of university presidents should be called to explore the possibility of a tougher code of violations. Among the penalties Mr. Byers said he would like to see for the most serious cases are more routine curtailment of scholarships, dismissals of coaching staffs and suspensions of team schedules for one year or more. This is the first time that Mr. Byers has acknowledged the size of the payments to athletes, which he estimates to be up to $20,000 or more a year, and he says the N.C.A.A. is losing ground in its attempt to enforce the rules and maintain the integrity of big- time college sports. ''We're not keeping up with the chase,'' Mr. Byers said. ''I've talked with our representatives and people I respect and the problem is much worse than I thought.''

American intelligence officials have told a Democratic congressman that two days after President Reagan made a joke about bombing the Soviet Union, a low-level Soviet military official ordered an alert of some of his troops in the Far East. An aide to the Congressman, Representative Michael D. Barnes of Maryland, said today that the alert was said to have been canceled 30 minutes later by higher authority. The aide said the intelligence officials had contended the alert was ''a non-event.''

An associate of a Soviet journalist who returned to Moscow last month asserts that the man, Oleg G. Bitov, was forcibly taken back by K.G.B. men because of fears that he would give evidence to Italian officials investigating the attempted assassination of Pope John Paul II. The friend, Anatoly Gladilin, a Russian emigre writer, wrote in an analysis of the case in Le Monde that Mr. Bitov had agreed to give written testimony in the case against a Bulgarian suspect, Sergei Ivanov Antonov, shortly before Mr. Bitov vanished from Britain in August. Mr. Bitov, a senior journalist for the weekly Literaturnaya Gazeta, was thought to have defected at the Venice Film Festival in September 1983 and to have been given asylum in Britain.

Many cities build subways. Seoul makes a crusade of it. Workers tunnel underground around the clock, just about every day of the year. Throughout the city, streets look like steel-plated moonscapes, pitted and deeply burrowed. Traffic, rarely smooth-flowing in the best of times, is unspeakable in many places.

A Soviet Foreign Ministry official today denied an assertion by Defense Secretary Caspar W. Weinberger that the Soviet Union had increased the number of nuclear missiles aimed at Western Europe. He said the number of missiles had not increased and that Mr. Weinberger made his statement to put pressure on Western Europe.

The Security Council voted today to extend the mandate of the United Nations force in southern Lebanon for six months amid suggestions that it might be expanded after Israeli troops are withdrawn. The extension of the mandate was approved 13 to 0 with the Soviet Union and the Ukraine abstaining.