diff --git a/planning/models.py b/planning/models.py
index dd17884..3fa6c7f 100644
--- a/planning/models.py
+++ b/planning/models.py
@@ -31,7 +31,7 @@ class Room(models.Model):
 
     @property
     def talks_by_date(self):
-        return self.talks.filter(start_date__isnull=False).exclude(Q(duration=0) | Q(event__duration=0)).order_by('start_date').all()
+        return self.talks.filter(start_date__isnull=False).exclude(duration=0, event__duration=0).order_by('start_date').all()
 
     @property
     def unscheduled_talks(self):