When is the Monsters of Rock show with 12 bands?
CREATE TABLE table_31803 (
    "Year" real,
    "Date" text,
    "Event" text,
    "Days" text,
    "Stages" text,
    "Acts" text
)
SELECT "Date" FROM table_31803 WHERE "Event" = 'monsters of rock' AND "Acts" = '12 bands'
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 is the Monsters of Rock show with 12 bands? ### Input: CREATE TABLE table_31803 (
    "Year" real,
    "Date" text,
    "Event" text,
    "Days" text,
    "Stages" text,
    "Acts" text
) ### Response: SELECT "Date" FROM table_31803 WHERE "Event" = 'monsters of rock' AND "Acts" = '12 bands'