What is the surface of the tournament with Sascha Kloer as the opponent?
CREATE TABLE table_35956 (
    "Date" text,
    "Tournament" text,
    "Surface" text,
    "Opponent" text,
    "Score" text
)
SELECT "Surface" FROM table_35956 WHERE "Opponent" = 'sascha kloer'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the surface of the tournament with Sascha Kloer as the opponent? ### Input: CREATE TABLE table_35956 (
    "Date" text,
    "Tournament" text,
    "Surface" text,
    "Opponent" text,
    "Score" text
) ### Response: SELECT "Surface" FROM table_35956 WHERE "Opponent" = 'sascha kloer'