The city council chose smart, wonky city staffer Ben Noble as its new central staff director yesterday, ending a months-long wait to see who would replace brainy economic analyst Saroja Reddy as head of the council’s research and analysis division. Central staffers, unlike council aides, work for the council as a whole; the council has frequently used their analysis to call bullshit on Mayor Nickels’s development proposals. Noble, who has been on central staff since 2000, has been serving as interim central staff director since Reddy took a job at the Gates Foundation.