President Clinton signed a bill setting up a federal board to overseethe District of Columbia's finances. By giving up some of the home rule power it has had since 1974, and allowing the five-member board to overrule the budgets ofMayor Marion Barry, the city wins permission to borrow hundreds of millions of dollars from the federal Treasury. That will help pay off a $722 million annual deficit. The new law requires the city to balance its budget within three years. Clinton has not yet named the board members, but says that he's askedformer Deputy Treasury Secretary Roger Altmanto be an adviser on the issue.