diff --git a/docs/api-guide/relations.md b/docs/api-guide/relations.md
index 979c3326c..fd53acbc8 100644
--- a/docs/api-guide/relations.md
+++ b/docs/api-guide/relations.md
@@ -501,7 +501,7 @@ For example, given the following model for a tag, which has a generic relationsh
         tagged_object = GenericForeignKey('content_type', 'object_id')
 
         def __unicode__(self):
-            return self.tag
+            return self.tag_name
 
 And the following two models, which may be have associated tags:
 
diff --git a/rest_framework/fields.py b/rest_framework/fields.py
index faf41e7a0..159784ea3 100644
--- a/rest_framework/fields.py
+++ b/rest_framework/fields.py
@@ -1189,7 +1189,7 @@ class DurationField(Field):
     def to_internal_value(self, value):
         if isinstance(value, datetime.timedelta):
             return value
-        parsed = parse_duration(value)
+        parsed = parse_duration(six.text_type(value))
         if parsed is not None:
             return parsed
         self.fail('invalid', format='[DD] [HH:[MM:]]ss[.uuuuuu]')
diff --git a/tests/test_fields.py b/tests/test_fields.py
index 8065c8260..c1d3e3a49 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -1069,6 +1069,7 @@ class TestDurationField(FieldValues):
         '3 08:32:01.000123': datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123),
         '08:01': datetime.timedelta(minutes=8, seconds=1),
         datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123): datetime.timedelta(days=3, hours=8, minutes=32, seconds=1, microseconds=123),
+        3600: datetime.timedelta(hours=1),
     }
     invalid_inputs = {
         'abc': ['Duration has wrong format. Use one of these formats instead: [DD] [HH:[MM:]]ss[.uuuuuu].'],