There's clearly a stand-alone riding of Oshawa. My riding of Durham would only take a small portion of north Oshawa, and by not including the names of other communities in the riding, such as Clarington or Scugog, you're essentially excluding larger historic communities within the riding.
Ma circonscription de Durham prendrait seulement une petite partie de North Oshawa, et en n'incluant pas les noms des autres collectivités dans la circonscription, par exemple Clarington ou Scugog, on exclut essentiellement de grandes collectivités historiques de la circonscription.