When Marja Ridder won the Women's singles who won the Men's singles?
CREATE TABLE table_14640 (
    "Year" text,
    "Men's singles" text,
    "Women's singles" text,
    "Men's doubles" text,
    "Women's doubles" text,
    "Mixed doubles" text
)
SELECT "Men's singles" FROM table_14640 WHERE "Women's singles" = 'marja ridder'
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: When Marja Ridder won the Women's singles who won the Men's singles? ### Input: CREATE TABLE table_14640 (
    "Year" text,
    "Men's singles" text,
    "Women's singles" text,
    "Men's doubles" text,
    "Women's doubles" text,
    "Mixed doubles" text
) ### Response: SELECT "Men's singles" FROM table_14640 WHERE "Women's singles" = 'marja ridder'