CREATE TABLE table_203_281 (id DECIMAL, "season" DECIMAL, "pitcher" TEXT, "decision" TEXT, "final\ score" TEXT, "opponent" TEXT, "location" TEXT)

roy oswalt opened for the astros for eight years in a row , seven of which were in minute maid park , but in what year did he start the season opener in petco park ?
SELECT "season" FROM table_203_281 WHERE "location" = 'petco park'
SELECT "season" FROM "table_203_281" WHERE "location" = 'petco park'