question: What's the Place of birth listed that has an Elevator of ALexander III, and an Elector of Ruggiero Di San Severino?
answer: SELECT place_of_birth FROM table_name_51 WHERE elevator = "alexander iii" AND elector = "ruggiero di san severino"
context: CREATE TABLE table_name_51 (place_of_birth VARCHAR, elevator VARCHAR, elector VARCHAR)