Which episode aired in the USA on 20 May 2005?
CREATE TABLE table_5256 (
    "Episode" real,
    "Title" text,
    "Airdate (Canada)" text,
    "Airdate (USA)" text,
    "CBS airdate" text
)
SELECT "Episode" FROM table_5256 WHERE "Airdate (USA)" = '20 may 2005'
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 episode aired in the USA on 20 May 2005? ### Input: CREATE TABLE table_5256 (
    "Episode" real,
    "Title" text,
    "Airdate (Canada)" text,
    "Airdate (USA)" text,
    "CBS airdate" text
) ### Response: SELECT "Episode" FROM table_5256 WHERE "Airdate (USA)" = '20 may 2005'