Lorenzo W. Jacobs, the District of Columbia's embattled Housing and Community Development director, showed up at a forum for mayoral candidates yesterday, and quickly found out that he, not the politicians, was the main attraction.

Both City Council Chairman Sterling Tucker and council member Marion Barry, two of the chief candidates in the Sept. 12 Democratic primary, told about 200 D.C. builders and realtors at the forum that they would fire Jacobs if they were elected.

Mayor Walter E. Washington, the other major candidate in the primary, gave Jacobs a tentative vote of approval, saying "It is not in my countenance to hold him as a scapegoat any more than you would in your own firm.

Jacobs sat grim-faced in the audience as Barry and Tucker spoke. But later he took a philosophical view of the dispute over this tenure.

Speaking of Barry and Tucker, Jacobs said, "They've said what they would do if a certain contingency occurs. I'm not concerned about that contingency happening."

Jacobs, who has headed the city's housing agency for nearly three years, described the statements as normal political jockeying. "Housing is a very emotional issue," he said. "When I came to the job I said I would make a difference and you just look at what has happened."

The General Accounting Office, among other groups, has attacked the city's housing agency for not developing an adequate program to pinpoint vacant houses, rehabilitate them and put them back on the market. "More needs to be done," the GAO said in a February report. "The District does not have a specific program for returning these houses to use."

Jacobs said the GAO assessment was "in general, accurate and fair," but "less positive than would appear to be appropriate."

Tucker charged in an interview after his presentation that Jacobs has provided "no direction, no policies, no plans" for more or better housing in the city.

Barry told the builders and realtors, "The city doesn't know where it's going" in its housing programs. "I'm as frustrated as you are."