Find the names of stadiums which have never had any event.
SELECT name FROM stadium WHERE id NOT IN (SELECT stadium_id FROM event)
SELECT name FROM stadium WHERE id NOT IN (SELECT stadium_id FROM event)
[{'name': 'Ferenc Puskás Stadion'}, {'name': 'Stade des Lumières'}, {'name': 'Northumberland Development Project'}, {'name': 'Arena Baltika'}]