Carl E. Heastie, the first African-American to serve as speaker of the New York Assembly, vowed on Saturday to use his powerful new position to call attention to the needs of black New Yorkers. “This is a tremendous opportunity for our community,” Mr. Heastie said at a rally hosted by the Rev. Al Sharpton in Harlem. As speaker, Mr. Heastie, a Bronx Democrat, will join the governor and the State Senate majority leader as Albany’s “three men in a room” who negotiate the state budget and other important matters. “All of you are going to be sitting at that table...