What is the production code of the episode that was watched by 3.81 million U.S. viewers? 
CREATE TABLE table_29054902_1 (production_code VARCHAR, us_viewers__million_ VARCHAR)
SELECT production_code FROM table_29054902_1 WHERE us_viewers__million_ = "3.81"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_29054902_1 (production_code VARCHAR, us_viewers__million_ VARCHAR) Question: What is the production code of the episode that was watched by 3.81 million U.S. viewers?  [/INST] SELECT production_code FROM table_29054902_1 WHERE us_viewers__million_ = "3.81" </s>