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_17427 ( "Year" real, "Mens singles" text, "Womens singles" text, "Mens doubles" text, "Womens doubles" text, "Mixed doubles" text )

### Question ###
Who won the womens singles when Marc Zwiebler won the men's singles?

### Accurate SQL ###

SELECT "Womens singles" FROM table_17427 WHERE "Mens singles" = 'Marc Zwiebler'