A man who was convicted in the stabbing of a Hasidic scholar in racial unrest that engulfed Crown Heights, Brooklyn, in 1991 was stabbed early Sunday in Upper Manhattan, the police said. The man, Lemrick Nelson Jr., 35, was found unconscious on an exit ramp of the George Washington Bridge about 2 a.m., according to the Fire Department. He had a stab wound behind his ear, and an ice pick was found nearby. He was taken to Harlem Hospital Center in stable condition. Investigators were looking into whether Mr. Nelson had been attacked after a traffic dispute, the police said....