What did the loss come from a Club of mumbles rfc?
CREATE TABLE table_6643 (
    "Club" text,
    "Played" text,
    "Drawn" text,
    "Lost" text,
    "Points for" text,
    "Points against" text,
    "Tries for" text,
    "Tries against" text,
    "Try bonus" text,
    "Losing bonus" text,
    "Points" text
)
SELECT "Lost" FROM table_6643 WHERE "Club" = 'mumbles rfc'
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 did the loss come from a Club of mumbles rfc? ### Input: CREATE TABLE table_6643 (
    "Club" text,
    "Played" text,
    "Drawn" text,
    "Lost" text,
    "Points for" text,
    "Points against" text,
    "Tries for" text,
    "Tries against" text,
    "Try bonus" text,
    "Losing bonus" text,
    "Points" text
) ### Response: SELECT "Lost" FROM table_6643 WHERE "Club" = 'mumbles rfc'