How many singles tournaments did Ludovic Walter win?
CREATE TABLE table_11900378_1 (
    tournament VARCHAR,
    singles_champions VARCHAR
)
SELECT COUNT(tournament) FROM table_11900378_1 WHERE singles_champions = "Ludovic Walter"
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: How many singles tournaments did Ludovic Walter win? ### Input: CREATE TABLE table_11900378_1 (
    tournament VARCHAR,
    singles_champions VARCHAR
) ### Response: SELECT COUNT(tournament) FROM table_11900378_1 WHERE singles_champions = "Ludovic Walter"