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_174491_2 ( fis_nordic_world_ski_championships VARCHAR, winner VARCHAR )

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

### Accurate SQL ###

SELECT fis_nordic_world_ski_championships FROM table_174491_2 WHERE winner = "Birger Ruud"