CREATE TABLE table_31458 ("Station" TEXT, "Metlink code" TEXT, "Line ( s ) " TEXT, "Service ( s ) " TEXT, "Serves" TEXT, "km from Wellington" TEXT, "Fare zone ( s ) " TEXT, "Opened" TEXT)

what is the metlink code that opened in 1908?
SELECT "Metlink code" FROM table_31458 WHERE "Opened" = '1908'
SELECT "Metlink code" FROM "table_31458" WHERE "Opened" = '1908'