CREATE TABLE table_26527 ("Episode" FLOAT, "Contest" TEXT, "Original airdate" TEXT, "Challengers  ( Female ) " TEXT, "Challengers  ( Male ) " TEXT, "Events" TEXT)

Which female challengers featured in episode 28?
SELECT "Challengers (Female)" FROM table_26527 WHERE "Episode" = '28'
SELECT "Challengers (Female)" FROM "table_26527" WHERE "Episode" = '28'