Mayor Bill de Blasio, promoting his message of income equality and empowering the less fortunate, pressed influential New York City business leaders on Thursday to raise their workers’ starting pay to $13 an hour. The liberal mayor made his call in front of a group that broadly supported his predecessor, billionaire businessman Michael Bloomberg, and at times had been skeptical of de Blasio’s agenda: a gathering of the well-heeled and powerful known as The Association for a Better New York. “I want to call on you, the business leaders gathered in this room, to do your part,” the mayor, a...