CREATE TABLE table_16574 ("Character" TEXT, "Portrayed by" TEXT, "First appearance" TEXT, "Last appearance" TEXT, "Duration" TEXT, "Episodes" TEXT)

Which episode did actor A. J. Buckley last appear in?
SELECT "Last appearance" FROM table_16574 WHERE "Portrayed by" = 'A. J. Buckley'
SELECT "Last appearance" FROM "table_16574" WHERE "Portrayed by" = 'A. J. Buckley'