What was the surface for the May 10, 2009 tournament?
CREATE TABLE table_name_91 (
    surface VARCHAR,
    date VARCHAR
)
SELECT surface FROM table_name_91 WHERE date = "may 10, 2009"
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 was the surface for the May 10, 2009 tournament? ### Input: CREATE TABLE table_name_91 (
    surface VARCHAR,
    date VARCHAR
) ### Response: SELECT surface FROM table_name_91 WHERE date = "may 10, 2009"