CREATE TABLE table_28211674_3 (u21_mens VARCHAR, mixed_restricted VARCHAR, u21_womens VARCHAR)

Who was the U21 Mens winner when Mike Marsden was the mixed restricted winner and Claire Nelson was the U21 Womens winner?
SELECT u21_mens FROM table_28211674_3 WHERE mixed_restricted = "Mike Marsden" AND u21_womens = "Claire Nelson"
SELECT "u21_mens" FROM "table_28211674_3" WHERE "Claire Nelson" = "u21_womens" AND "Mike Marsden" = "mixed_restricted"