How many episodes had production number 2x13?
CREATE TABLE table_3537 (
    "Series #" real,
    "Season #" real,
    "Episode Title" text,
    "Original airdate" text,
    "Prod. No." text
)
SELECT COUNT("Season #") FROM table_3537 WHERE "Prod. No." = '2x13'
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 episodes had production number 2x13? ### Input: CREATE TABLE table_3537 (
    "Series #" real,
    "Season #" real,
    "Episode Title" text,
    "Original airdate" text,
    "Prod. No." text
) ### Response: SELECT COUNT("Season #") FROM table_3537 WHERE "Prod. No." = '2x13'