CREATE TABLE table_204_624 (id DECIMAL, "school" TEXT, "team name" TEXT, "town" TEXT, "county" TEXT, "enrollment  ( 2010-11 & 2011-12 ) " DECIMAL, "primary mshsaa class*" DECIMAL, "football class" DECIMAL)

what school has 3 football classes but only has 638 student enrollment ?
SELECT "school" FROM table_204_624 WHERE "football class" = 3 AND "enrollment (2010-11 & 2011-12)" = 638
SELECT "school" FROM "table_204_624" WHERE "enrollment (2010-11 & 2011-12)" = 638 AND "football class" = 3