when was the premiere when a 3.3 millions of North American watched the episode whose writer was Rob Wright?
CREATE TABLE table_21313498_1 (original_air_date VARCHAR, us_viewers__millions_ VARCHAR, written_by VARCHAR)
SELECT original_air_date FROM table_21313498_1 WHERE us_viewers__millions_ = "3.3" AND written_by = "Rob Wright"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_21313498_1 (original_air_date VARCHAR, us_viewers__millions_ VARCHAR, written_by VARCHAR) Question: when was the premiere when a 3.3 millions of North American watched the episode whose writer was Rob Wright? [/INST] SELECT original_air_date FROM table_21313498_1 WHERE us_viewers__millions_ = "3.3" AND written_by = "Rob Wright" </s>