What was going on when I was born?

Charles T. Manatt, chairman of the Democratic National Committee, today announced his intention to form a ''party unity task force'' to resolve disputes among the three Democratic Presidential candidates. Earlier in the day, Walter F. Mondale, Gary Hart and the Rev. Jesse Jackson all indicated a general willingness to participate in discussions that, according to party leaders, would be designed to prevent damaging public disputes among the candidates and their supporters at the Democratic National Convention in July. Even as Mr. Manatt issued his call for unity, however, the candidates continued to hack at one another in campaign stops in Texas, which holds caucuses Saturday, and in Ohio, which holds an important primary next Tuesday. Response to Disclosure The Manatt proposal came in response to the disclosure that Mr. Mondale, Mr. Jackson and Robert S. Strauss met privately in Dallas on Wednesday night to discuss what Mr. Jackson called ''a conflict resolution apparatus,'' with Mr. Strauss as mediator, to heal the divisions created by the battle for the nomination. An aide said that Mr. Manatt regarded this meeting as a ''trial balloon'' from the Mondale camp. Some party leaders added that Mr. Manatt's prompt response was meant to be a signal that he, not Mr. Strauss, should fill the role of mediator among the candidates.

The Reagan Administration is confident that Jose Napoleon Duarte, the leader of El Salvador's Christian Democrats, will win the presidential runoff election Sunday and is planning to invite him to Washington later this month, State Department officials said today. The object, they said, would be to help gain Congressional passage of additional funds for El Salvador. If Mr. Duarte, who is regarded as a moderate, does win, President Reagan will probably address the nation next week on behalf of the Salvadoran aid, the officials said. Officially, the Administration is neutral between Mr. Duarte and his conservative opponent, Roberto d'Aubuisson, head of the Nationalist Republican Alliance. But privately there is no question that senior officials would much prefer Mr. Duarte to win because of Mr. d'Aubuisson's reported links to right-wing death squads.

Congressional experts on military matters generally said today that President Reagan's latest plan to trim the Pentagon budget did not go far enough. They predicted Congress would make additional cuts as it grappled with reducing the budget deficit in the months ahead. As part of those cuts, many lawmakers now believe Congress could delay, or even kill outright, the costly MX missile. One key supporter of the missile said it could lose by as many as 30 votes when it comes to a vote on the House floor later this month.

Only the purest of the purists are grumbling here this week, disappointed that the 20 horses who will run in the 110th Kentucky Derby Saturday may be a substandard and uninspiring bunch. To everyone else in Louisville, including most of the 130,000 who will actually be at Churchill Downs for the race, the Kentucky Derby has little more to do with good horses than a fraternity beer blast does with the finer points of Greek philosophy. The Derby itself, the one horse race of the year that interests those not partial to the sport, is almost an anticlimax after a week of revelry and civic pride. Derby Week is a nonstop festival that seems to have captured the imagination and the support of an entire city. There is a Great Steamboat Race, a Great Balloon Race, a Chow Wagon Festival, a Blue Grass Picnic and dozens of other functions that receive as much attention on local newscasts as developments in Washington or Beirut.

The way Lorraine Wang recalls it, one day a friend approached her and her husband, An Wang, the chairman of Wang Laboratories, and mentioned that the roof was literally falling in at Boston's main performing arts center. The Wangs were not particularly patrons of the arts, Mrs. Wang said, ''but something had to be done.'' So when her Shanghai-born husband asked her if they should help, she replied, ''Why not?'' And without further discussion he pledged $4 million to save the theater from being closed. This was but one of a series of recent philanthropic actions that have made the 63-year-old Chinese immigrant, who came to the United States in 1945, Boston's current leading benefactor.

The Polish leader, Gen. Wojciech Jaruzelski, signed a 15-year economic pact with the Soviet Union today. Although no details of the agreement were made public, it appeared to offer renewed Soviet assistance to Poland's faltering economy in return for accelerated efforts to bind the country more tightly into the Soviet economic orbit. The pact was signed for the Kremlin by Konstantin U. Chernenko, the Soviet leader. Mr. Chernenko said in a speech at a banquet later that it was ''a document of major political importance'' that provided for economic, scientific and technical cooperation between the two countries up to the year 2000. Seeks Soviet Aid The presence of high-ranking economic officials on both sides in the Kremlin talks gave weight to reports that General Jaruzelski came here seeking more Soviet economic aid, including hard currency credits to ease Poland's strained financial relations with the West.

Fourteen students have been expelled from the Choate Rosemary Hall School following the arrest of one of them on charges of trying to smuggle $300,000 worth of cocaine into the country, school officials said yesterday. Administrators of Choate said an investigation by the school into drug abuse, begun after the arrest last month, indicated that those expelled ''were involved'' with the arrested student. All 14 were juniors and seniors.

Esmark Inc., the big Chicago conglomerate, said yesterday that after months of behind-the-scenes talks, it had agreed to a $2.4 billion takeover by Kohlberg, Kravis, Roberts & Company, a leading New York investment house. As part of the agreement, called a management takeover, executives of Esmark will also invest in their own company, which has extensive interests in foods, personal-care products and industrial products. Its brand names includes Avis, the car rental company; the Swift, Hunt and Wesson food companies; Max Factor cosmetics; International Playtex, women's undergarments and personal products, and Estronics, high-fidelity equipment. Donald P. Kelly, chairman and chief executive of Esmark, is to remain in command and, along with other top executives, would have what insiders described as a ''significant'' investment in the company.

To the people of this hilly fishing village, the hub of Canada's scallop fishing industry, their economic fate hangs on a case that the United States has been pressing before the International Court of Justice at The Hague. The United States says it owns the Georges Bank, an area between Nova Scotia and New England where scallop fishing is done. Canada says it owns slightly less than half of it. Canada contends that, if the United States wins, the effect might be to force 3,600 fishermen and workers in support industries in Lunenburg and other areas along the Nova Scotia coast off the job.

Prime Minister Margaret Thatcher suffered a sharp political reversal Thursday on the fifth anniversary of her move to 10 Downing Street. The Conservative party was turned out of office in several important cities and barely managed to hold onto two seats in the House of Commons that it has always won by hefty margins. Results of local elections in England, Scotland and Wales, excluding London and a few other areas, which were declared this morning, showed that the Tories had lost control of the councils in Birmingham, Edinburgh, Soughampton, Exeter and elsewhere. The loss of Birmingham, England's second largest city, where the conservative had cut taxes sharply and proclaimed themselves a ''model administration,'' was a especially bitter blow.

Pope John Paul II preached a sermon of reconciliation today in this city in which the Government crushed a student uprising four years ago. John Paul, addressing a silently attentive audience of about 50,000 at a mass in the city stadium, said: ''I am keenly aware of the deep wounds that pain your hearts and souls from personal experiences and from recent tragedies, which are difficult to overcome from a merely human point of view, especially for those of you from Kwangju.'' Speaking of ''the grace of reconciliation,'' he added: ''This part of Christ's saving message is particularly relevant for those who are haunted by the memory of the unfortunate events of this place. ''By accepting the consequences of our baptismal commitment, we become instruments of reconciliation and peace in the midst of dissension and hatred. In this way, as effective signs of Christ's healing power working in us, we ease the pain of injured hearts that are filled with anxiety and bitterness.''

The Rev. Jesse Jackson said today that he had sent an appeal to President Hafez al- Assad of Syria urging him to release three Israeli diplomats. Mr. Jackson sent a telegram to the Syrian President Thursday from San Antonio, where he is campaigning for the Democratic nomination for President.