What was going on when I was born?

After 10 days of deliberation and a temporary deadlock in the trial of Erin Leslie Fleming, Groucho Marx's longtime companion, jurors today awarded the Bank of America more than $450,000 in a judgment against her. As executor of the comedian's estate, the Bank of America was awarded $221,843.09 in compensatory damages and $250,000 in punitive damages. The bank had charged that Miss Fleming had manipulated the elderly comedian to obtain money and gifts. The bank had sued Miss Fleming for $500,000 in punitive damages, and recovery of two houses, a Mercedes-Benz, municipal bonds and other gifts totaling more than $400,000 that it said she had received improperly.

''ICAN'T stand living with things I can't use,'' says Robert Bishop, the director of the Museum of American Folk Art in Manhattan. The man who in six years has helped shape the institution into the major folk-art museum in the country has in fact managed to keep his own home from becoming a museum. ''I'm not a collector in the truest sense - I've never pursued an object only because of its period,'' he says. There may be 17th- and 18th-century pieces throughout the apartment, along with 19th-century Shaker furniture, but the interior is an unpretentious, comfortable and personal environment in which Mr. Bishop, 44 years old, spends a lot of time working.

''When it comes to intermediate nuclear missiles in Europe, it would be better to have none than to have some.

An Associated Press dispatch Tuesday erroneously quoted a spokesman for the Weyerhaeuser Company in regard to the deposit of wastes at the Stringfellow Pits site in California. The spokesman, Tom Ambrose, said Weyerhaeuser ranked 11th in volume among 199 companies known to have used the site, but he said the Weyerhaeuser wastes were nontoxic.

International A new American arms control plan was announced by President Reagan. In a televised statement, he offered to reduce the planned deployment of new American medium-range missiles in Western Europe in exchange for a reduction in the deployment of Soviet medium-range missiles in Europe and Asia that would result in each side having the same total number of warheads. (Page A1, Column 6.) NATO allies hailed President Reagan for his new proposal for limiting medium-range nuclear missiles and called on Moscow for a quick and constructive response. (A10:4-6.)

The official in charge of bookings for New York City's new Convention Center said yesterday that ''it would be disastrous'' for the city's economy and reputation if the center's opening was delayed beyond the middle of next year. ''Any mention of a delay seriously undermines our credibility and standing in the industry,'' said Jerry Lowery, the executive director of the New York Convention Center Operating Authority. ''A declaration of about a year's delay could leave the state open to lawsuits from the shows who have relied on our booking, expended dollars to promote their shows and now have nowhere to go.'' Delay of at Least a Year An official of the state's Urban Development Corporation has warned that completion of the Convention Center could be delayed by at least a year.

The Social Security Administration said today that it had no plans to reconsider a $100 million computer contract it awarded a Florida company, despite charges by the Securities and Exchange Commission that the company used fraud and deceit to obtain the contract. Social Security officials said that they were, in fact, considering exercising an option to buy additional equipment from the company, the Paradyne Corporation of Largo, Fla. Agency's Largest Contract The S.E.C. charged Friday, in a civil complaint filed in Federal District Court in Tampa, Fla., that Paradyne had violated Federal securities laws in obtaining the 1981 contract, described as the largest in the history of the Social Security Administration. According to the agency, Paradyne intentionally misled Social Security officials by repackaging the products of another company and demonstrating an information-coding device that was ''nothing more than an empty box with blinking lights.'' Paradyne today denied the charges.

The Legal Aid Society is challenging New York City and State on what it characterizes as inhumane care of homeless families with children. The society is charging that the families are frequently denied emergency housing or, if granted such housing, are placed in quarters that are dangerous and uninhabitable. The society is seeking a court order to require the city and state to provide the families with safe and adequate emergency housing and also promptly assist them in finding acceptable permanent housing. The society says it plans to file a class-action suit today in State Supreme Court in Manhattan against the city and the state. The suit is being brought by 16 homeless families with children, on behalf of themselves and all others in a similar situation.

A new Census Bureau analysis of the sharp decline in the use of mass transit has rekindled a dispute as to whether public policy should be used to maintain and revive old depressed communities or to help the movement of people to new places of growth. The analysis attributes the transit decline to the dispersal of workers and jobs away from urban centers. It asserts that public officials have unrealistic expectations that good public transportation can hold big-city populations in place. Paul N. Fulton, chief of the bureau's Journey-to-Work and Migration Statistics branch, prepared the analysis, which was based on findings of the 1980 Census that only about 6 percent of American workers commuted by public transit, a decline from 9 percent in 1970. Almost half a million fewer workers used public transportation in 1980 than a decade earlier despite a large increase in the total work force.

British National Oil has proposed price cuts of up to 75 cents a barrel on North Sea oil, clearing the way for the first test of OPEC's new price structure. But the British, in pricing their best grade of crude, were careful not to breach the $30-a-barrel floor that OPEC has set under threat of a price war. (Page A1.) Soviet balance of payments accounts may suffer a $5 billion deficit by 1983 because of falling oil prices, analysts in Washington say. Moscow has already increased oil shipments to the West, and some officials expect it to cut those to Eastern Europe. (D3.)

AT 6 A.M. a producer of television commecials gts down to business in his East Side dining room. At midnight a fashion designer follows through on a creative burst in her TriBeCa loft. Twenty-four hours into the debugging of a program, a computer software designer is still at work in the comfort of his Upper West Side bedroom. Such hours are routine for the growing ranks of New Yorkers whose apartments and lofts double as their offices. They get up when they please; they pace their schedules in idiosyncratic ways; they call it a day when they no longer feel productive. As a fashion designer who has worked at home for the last 12 years puts it: ''No two days are ever the same.'' In New York, however, this freedom is seldom achieved easily. It requires design ingenuity, and sometimes a substantial remodeling budget, to make the merger of home and office work. Some solutions demand little compromise: an office may be cleverly disguised, or corralled in a corner. Sometimes the office gains the upper hand; for example, a brownstone apartment whose owners sleep in their living room and work in their bedroom.

Pan American World Airways announced yesterday that it would temporarily cut some fares on its domestic routes to about half those recently proposed by American Airlines. The move would partly erode American's effort - widely supported by other carriers - to raise fares and limit discounts. Aside for such heavily traveled routes as New York to Florida and New York to the West Coast, American's proposal, however, remained largely unchallenged by the Pan American announcement. In addition, Pan Am's lower fares on these two routes would be offered on a limited basis for seats still available after the airline's international passengers had been accommodated.