Fix distinct type row mapping

README.rst

@@ -289,6 +289,10 @@ Nim Type         Postgres Type           SQLite Type
 `JsonNode`_      `jsonb`_
 ===============  ======================  =================
 
+Distinct types backed by a supported type are parsed through their backing
+type and then converted to the distinct type. This also applies when the
+distinct type is nested in an `Option`_ or `seq`.
+
 .. [#f1] Note that this implies that all `NULL`-able fields should be typed
          as optional using `Option[fieldType]`. Conversely, any fields with
          non-optional types should also be constrained to be `NOT NULL` in