CREATE TABLE table_19428 ("School Year" TEXT, "Class A" TEXT, "Class AA" TEXT, "Class AAA" TEXT, "Class AAAA" TEXT, "Class AAAAA" TEXT)

Who was the Class AAAA champion in 2006-07?
SELECT "Class AAAA" FROM table_19428 WHERE "School Year" = '2006-07'
SELECT "Class AAAA" FROM "table_19428" WHERE "School Year" = '2006-07'