Table schema:
CREATE TABLE table_27484208_1 (world_rank_by_arwu_ VARCHAR, _2013 VARCHAR, members VARCHAR)

Question: What was the world rank by ARWU in 2013 of the University of Tübingen?
SQL: SELECT world_rank_by_arwu_, _2013 FROM table_27484208_1 WHERE members = "University of Tübingen"