diff --git a/aurora/models.py b/aurora/models.py
index 4792f4a..81963a0 100644
--- a/aurora/models.py
+++ b/aurora/models.py
@@ -228,6 +228,7 @@ class Moderation(AuroraGuildModel):
 
         case_safe = case.copy()
         case_safe.pop("guild_id")
+        case_safe["duration"] = str(case_safe["duration"]) if case_safe["duration"] else None
         case_safe["timestamp"] = case_safe["timestamp"].timestamp()
         case_safe["end_timestamp"] = case_safe["end_timestamp"].timestamp() if case_safe["end_timestamp"] else None
         case_safe["changes"] = dumps(case_safe["changes"])