Index: django/db/models/sql/query.py
===================================================================
--- django/db/models/sql/query.py	(revision 7462)
+++ django/db/models/sql/query.py	(working copy)
@@ -392,7 +392,7 @@
         elif self.default_cols:
             cols = self.get_default_columns(True, with_aliases, col_aliases)
             result.extend(cols)
-            aliases.extend(cols)
+            aliases.extend([col.partition(' AS ')[2] or col for col in cols])
         for table, col in self.related_select_cols:
             r = '%s.%s' % (qn(table), qn(col))
             if with_aliases and col in col_aliases:
@@ -434,8 +434,11 @@
                     c_alias = 'Col%d' % len(col_aliases)
                     result.append('%s.%s AS %s' % (qn(alias),
                         qn2(field.column), c_aliase))
+                    col_aliases.add(c_alias)
                 else:
                     result.append('%s.%s' % (qn(alias), qn2(field.column)))
+                    if with_aliases:
+                        col_aliases.add(field.column)
             else:
                 result.append((alias, field.column))
         return result