What is the name of the leader of the Roman Catholic Church?

First of all, there is no "Roman" Catholic Church. "Roman" Catholic is a slur term first popularized in England after the protestant revolt. The leader of the Catholic Church is God, specifically His Son, Our Blessed Lord, Jesus Christ, who sent the Holy Spirit to guide the Church until the end of time. His appointed Vicar on earth is the Pope, the first of which was St. Peter (see Matthew 16:17-19) and the current successor of whom, is Francis.