What was going on when I was born?

The national unemployment rate held steady in June for the fifth straight month, the Government reported today. It was the latest of several recent signs that declining interest rates have yet to reinvigorate the economy. The overall jobless rate, including military personnel, stood at 7.2 percent, with the number of unemployed at 8,413,000, the same number as in May. The civilian unemployment rate, which excludes the military, was also unchanged last month at 7.3 percent. Total employment in June was 108,072,000, with 106,370,000 civilians and 1,702,000 in the armed forces.

Seven hours, 46 hits, 29 runs and 19 innings after the first pitch was thrown Thursdaynight, the Mets finally beat the Atlanta Braves this morning, 16-13. No game had gone so many innings this season; no game in history had ended at such a late - or was it early? - hour. At the end, at 3:55 A.M., the game seemed like a blur filled with emotional highs and lows, including the decisive five-run rally in the 19th by the Mets. The game took 6 hours 10 minutes to complete, plus a 41-minute rain delay. It finally ended with a Fourth of July fireworks show for the estimated 8,000 fans who withstood the rain and the drama and remained at Atlanta-Fulton County Stadium. And when the long night's journey into day was over - when Rick Camp, the pitcher who had delivered an unlikely home run in the 18th inning, finally struck out with two men on base to send everyone wearily home - all that remained were superlatives.

A medical panel ruled today that two white physicians who examined the black activist Steve Biko before his death in detention in 1977 were guilty of improper conduct and that one of them displayed ''disgraceful behavior.'' Mr. Biko, leader of the black consciousness movement in South Africa, was the most prominent black activist to die in police custody in recent years, and he is viewed by many blacks as a martyr in the fight against white minority rule. The finding by a panel made up of a Supreme Court judge and five doctors of South Africa's Medical and Dental Council, the body that oversees the country's medical and dental practices, came after a long series of hearings. Driven Manacled 800 Miles Its conclusion seemed to confirm the accusations of black activists and other physicians that Mr. Biko was suffering from brain damage when the two doctors allowed him to be taken 800 miles, naked and manacled in the back of a Land-Rover, from Port Elizabeth to Pretoria. He died the next day.

Several pieces of the Air-India Boeing 747 that crashed off Ireland June 23, including a panel believed to contain two recording devices, were located on the ocean floor today by an unmanned, remote-controlled submarine. Those investigating the crash say they believe the two recording devices, which monitored the airliner's operating systems and recorded the voices of its crew, may hold vital clues as to whether the plane was destroyed by a bomb, or whether the crash was caused by some structural failure or human error. The finds included portions of the cabin, galley and tail and what appear to be bodies of some of the 329 victims. One of the pieces found, a panel bearing the slogan ''Your Palace in the Sky,'' is thought to hold the flight recorders.

The United States has failed to win any firm backing so far in its effort to enlist international support for closing down Beirut International Airport on the ground that it is a safe haven for terrorists, Reagan Administration officials said today. The American plan has provoked a wave of protest among Arab nations, and today a delegation said to represent all Arab countries asked the State Department to reconsider the action. The Lebanese Government, in a letter to the United Nations Secretary General, said the plan was ''out of proportion'' to the harm done by the hijacking. Some State Department officials said the plan to ''isolate'' the airport, announced last Monday afternoon, had been pushed through by the White House to show that the United States was going to take some action in retaliation for the hijacking of Trans World Airlines Flight 847. The 39 remaining passengers and crew from that plane were freed on Sunday.

Three months ago the sprawling Bath Iron Works complex rang with cheers as thousands of workers heard the news that the shipyard had won a new Navy contract that could bring it billions of dollars of work in the decades to come. But last Sunday all construction stopped at this proud old yard. Its shops and landmark cranes, the tallest structures in the town of Bath, are still. Its production workers have gone out on strike, refusing to believe the Iron Works's insistence that to get the contract the company had to make a bid based on lower wage and benefit costs than it pays. The company says that to build the first ship of a new class of guided-missile destroyers, a project that could ultimately bring $4.5 billion or more in work, these labor costs must be trimmed.

Spain's new Cabinet was sworn in today amid widespread assertions that Prime Minister Felipe Gonzalez had been politically weakened by a dispute over the Government shake-up. King Juan Carlos administered the oath to the 15-member Cabinet, which includes new leaders for six ministries, in a brief ceremony. Newspapers, foreign diplomats and many political leaders from the right to the left said today that the Cabinet changes, designed to strengthen the Socialist Government, had backfired, at least temporarily. They said Mr. Gonzalez, who has been Prime Minister for two and a half years, had allowed a minor Government facelift to develop into a showdown that ended in the rancorous departure of two leading figures, Foreign Minister Fernando Moran and Economy Minister Miguel Boyer.

In the last 10 months, 37 witnesses and experts at the Hitler diaries trial have lent their insights into one of the great journalistic frauds of the century. Yet those who have followed the marathon trial here have been left unsatisfied, as if they had read an elaborate whodunit without an ending. It is not only that Dietrich Klein, the cool, even-toned prosecutor, has failed to establish what happened to $3.1 million that the Hamburg weekly Stern is said to have given to one of its reporters, Gerd Heidemann, to secure the bogus diaries. The trial has also raised the question: Who really defrauded whom?

The party of Prime Minister Robert Mugabe took a solid lead today in Zimbabwe's first general election since the country gained independence in 1980, and it appeared that he would gain the clear majority he and political analysts had been predicting. But the party of Joshua Nkomo, Mr. Mugabe's main rival, was winning decisively in Mr. Nkomo's stronghold of Matabeleland, underscoring the deep ethnic, geographic and political divisions remaining in this southern African nation. [Late returns indicated that Mr. Mugabe's party had taken 57 seats to 12 for Mr. Nkomo's group, Reuters reported. Results were not yet available for 10 seats, and voting in one constituency was put off because of a candidate's death.] About three million blacks voted in the four-day election.

Prime Minister Margaret Thatcher suffered a nasty political shock today as her party finished a feeble third in a closely watched by-election in Wales. In the voting in Brecon and Radnor, a sprawling rural constituency in the southeastern part of the principality, Richard Livsey, a Liberal, won a narrow victory over Richard Willey of Labor. Mr. Livsey's triumph gave a sorely needed boost to the Liberal-Social Democratic Alliance, which needs continuing by-election victories to lend credence to its assertion that it should be taken seriously as a third major force in British politics. It was a good showing too for the recently rejuvenated Labor Party, which did not count Brecon and Radnor among the seats it was likely to win. It is among the most agricultural areas in the country, and Labor has had little appeal for farmers.

Warsaw Pact maneuvers involving 23,000 Soviet, Hungarian and Czechoslovak troops ended in Hungary today, the official Hungarian press agency reported. The maneuvers, code named Danube 85, began three weeks ago and involve both conventional weapons and weapons of mass destruction, according to official reports.

The Honduran Army today turned over to West German diplomats a West German woman captured June 14 by Indian rebels in Nicaragua. The woman, Eva Regine Schemann, an ecologist working for the Nicaraguan Government, was captured by a unit of the Misura guerrilla group near the isolated Caribbean town of Puerto Cabezas, about 180 miles northeast of Managua near the Honduran border. Miss Schemann was released on the Honduran-Nicaraguan border to Honduran Army troops, who then turned her over to West German diplomats at the main Honduran air base outside the capital of Tegucigalpa, the army announced.