Mr. Baldwin said that he would probably sit out in 2013 but run in a later election, and that he wanted to educate himself about the mayor’s office first. He is talking with two top universities about enrolling in a master’s program in politics and government “to help me better understand what the fiscal imperatives of that job are,” he said. “What’s the reality of the city unions, of contracts, agreements, teachers, infrastructure, decentralizing, everything? And utilities, Con Ed, the M.T.A. — how does it all work?”