TheFork users who ate in Orgon have said really good things about Le Côté Jardin, Le Relais du Coche and Mas de Cure Bourse. Maybe you should give them a try!
Some of the more popular Duck Liver restaurants having a terrace in Orgon according to TheFork users include:
Le Côté Jardin, with a 8.7 rating
Le Relais du Coche, with a 9.2 rating
Mas de Cure Bourse, with a 8.9 rating