Which Established has a League of ontario australian football league?
CREATE TABLE table_12661 (
    "Club" text,
    "League" text,
    "Sport" text,
    "Established" text,
    "Championships" real
)
SELECT "Established" FROM table_12661 WHERE "League" = 'ontario australian football league'
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: Which Established has a League of ontario australian football league? ### Input: CREATE TABLE table_12661 (
    "Club" text,
    "League" text,
    "Sport" text,
    "Established" text,
    "Championships" real
) ### Response: SELECT "Established" FROM table_12661 WHERE "League" = 'ontario australian football league'