SELECT "station" FROM table_203_839 ORDER BY "opened" LIMIT 1
the first opened station
CREATE TABLE table_203_839 (
    id number,
    "station" text,
    "type" text,
    "latitude" text,
    "longitude" text,
    "el. (m)" number,
    "opened" number,
    "closed" number,
    "coordinates" text
)