What was the world rank by ARWU in 2013 of the University of Tübingen?
create table table_27484208_1 (world_rank_by_arwu_ varchar, _2013 varchar, members varchar, PRIMARY KEY (world_rank_by_arwu_))
select world_rank_by_arwu_, _2013 from table_27484208_1 where members = "university of tübingen"