Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_30166 ( "Series episode" real, "Season episode" real, "Title" text, "Directed by" text, "Written by" text, "Original air date" text, "U.S. viewers (in million)" text )

### Question ###
What was the episode number for the episode viewed by 5.68 million viewers?

### Accurate SQL ###

SELECT "Season episode" FROM table_30166 WHERE "U.S. viewers (in million)" = '5.68'