What is the surface of the tournament with Sascha Kloer as the opponent?
CREATE TABLE table_name_37 (surface VARCHAR, opponent VARCHAR)
SELECT surface FROM table_name_37 WHERE opponent = "sascha kloer"
### Context: CREATE TABLE table_name_37 (surface VARCHAR, opponent VARCHAR) ### Question: What is the surface of the tournament with Sascha Kloer as the opponent? ### Answer: SELECT surface FROM table_name_37 WHERE opponent = "sascha kloer"