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_69550 ( "Year" real, "Men's singles" text, "Women's singles" text, "Men's doubles" text, "Women's doubles" text, "Mixed doubles" text )

### Question ###
What player played women's singles when marcus ellis heather olver played mixed doubles?

### Accurate SQL ###

SELECT "Women's singles" FROM table_69550 WHERE "Mixed doubles" = 'marcus ellis heather olver'