CREATE TABLE table_203_536 (id DECIMAL, "#" DECIMAL, "date" TEXT, "opponent" TEXT, "score" TEXT, "win" TEXT, "loss" TEXT, "save" TEXT, "crowd" DECIMAL, "record" TEXT)

which opponent did they play against before the play date of april 12 ?
SELECT "opponent" FROM table_203_536 WHERE id = (SELECT id FROM table_203_536 WHERE "date" = 'apr 12') - 1
SELECT "opponent" FROM "table_203_536" WHERE "id" = (SELECT "id" FROM "table_203_536" WHERE "date" = 'apr 12') - 1