Mayor-elect Zohran Mamdani has tapped a controversial lawyer who defended an al Qaeda terrorist and a radical anti-Israel campus leader at Columbia for a “high-ranking” position at City Hall, The Post has learned. Ramzi Kassem, who is also a law professor at City University of New York and a member of Mamdani’s transition team for legal affairs, is the top candidate for Chief Counsel, the most important advisory role in the mayor’s office, according to a source close to the transition team. Kassem, 47, was one of the attorneys who defended Mahmoud Khalil, a Syrian-born leader of the pro-Palestinian encampment...