CREATE TABLE table_36555 ("School Year" TEXT, "Class A" TEXT, "Class AA" TEXT, "Class AAA" TEXT, "Class AAAA" TEXT, "Class AAAAA" TEXT)

what AAA class has a school year of 1989-90?
SELECT "Class AAA" FROM table_36555 WHERE "School Year" = '1989-90'
SELECT "Class AAA" FROM "table_36555" WHERE "School Year" = '1989-90'