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_21696 ( "Winner" text, "Country" text, "Winter Olympics" text, "FIS Nordic World Ski Championships" text, "Holmenkollen" text )

### Question ###
What years did Birger Ruud win the FIS Nordic World Ski Championships?

### Accurate SQL ###

SELECT "FIS Nordic World Ski Championships" FROM table_21696 WHERE "Winner" = 'Birger Ruud'