What's the production code of the episode seen by 11.64 million US viewers?
CREATE TABLE table_12159115_2 (
    production_code VARCHAR,
    us_viewers__millions_ VARCHAR
)
SELECT production_code FROM table_12159115_2 WHERE us_viewers__millions_ = "11.64"
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's the production code of the episode seen by 11.64 million US viewers? ### Input: CREATE TABLE table_12159115_2 (
    production_code VARCHAR,
    us_viewers__millions_ VARCHAR
) ### Response: SELECT production_code FROM table_12159115_2 WHERE us_viewers__millions_ = "11.64"