That is the list of known candidates and competitive races. At any time before the filing deadline, the party may convince other candidates to run (NPCs are free). For each contested election below I have included a rough estimate of polling. It shouldn't be seen as party membership in that district, simply how the vote would go without player intervention.
Each party should select four races that they wish to actively roleplay. I would recommend that you chose the races that have your party losing by a small majority. In states that are at-large, you will need to select the entire state. This list is also required by the filing deadline (Saturday night).
You'll notice that some active players are being opposed, but none have serious challengers. You should consider the opposition as flattery, as the admin team is giving you an opportunity to roleplay your own election if you so desire.