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_28211674_3 (u21_mens VARCHAR, mixed_restricted VARCHAR, u21_womens VARCHAR)

### Question ###
Who was the U21 Mens winner when Mike Marsden was the mixed restricted winner and Claire Nelson was the U21 Womens winner? 

### Accurate SQL ###

SELECT u21_mens FROM table_28211674_3 WHERE mixed_restricted = "Mike Marsden" AND u21_womens = "Claire Nelson"