CREATE TABLE table_35956 ("Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Opponent" TEXT, "Score" TEXT)

What is the surface of the tournament with Sascha Kloer as the opponent?
SELECT "Surface" FROM table_35956 WHERE "Opponent" = 'sascha kloer'
SELECT "Surface" FROM "table_35956" WHERE "Opponent" = 'sascha kloer'