CREATE TABLE table_67704 ("Years" TEXT, "Coach" TEXT, "Seasons" FLOAT, "Wins" FLOAT, "Losses" FLOAT, "Ties" TEXT, "Pct." TEXT)

Which Notre Dame coach lost 15 games?
SELECT "Coach" FROM table_67704 WHERE "Losses" = '15'
SELECT "Coach" FROM "table_67704" WHERE "Losses" = '15'