diff --git a/aiopg/sa/result.py b/aiopg/sa/result.py
index 1e47c4cb..ce1a7b6e 100644
--- a/aiopg/sa/result.py
+++ b/aiopg/sa/result.py
@@ -100,7 +100,6 @@ def __init__(self, result_proxy, metadata):
         self._keymap = keymap = {}
         self.keys = []
         dialect = result_proxy.dialect
-        typemap = dialect.dbapi_type_map
         assert dialect.case_sensitive, \
             "Doesn't support case insensitive database connection"
 
@@ -121,9 +120,7 @@ def __init__(self, result_proxy, metadata):
             name, obj, type_ = (
                 colname,
                 None,
-                result_map.get(
-                    colname,
-                    typemap.get(coltype, sqltypes.NULLTYPE))
+                result_map.get(colname, sqltypes.NULLTYPE),
             )
 
             processor = type_._cached_result_processor(dialect, coltype)