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

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'