The rules state that advisors are placed FIRST (or the player can abstain, allowing him to move a house). THEN the player(s) who won the election brings new houses onto the board.
The rule summary that comes with the game has that order reversed, i.e., FIRST houses are placed, THEN advisors are moved/abstained from.
The order is actually really important, particularly during the endgame, because if I can win a district and place houses first, I could then abstain from taking control of an advisor to move one of those just-placed houses to a district where I need only more house to build the game-winning palace.
I would have to go with the rules on this one. There are several passages that make me think this - i will list them below. underlined parts are the key phrases
Standing an advisor in an area
When a player takes control of an advisor, he must immediately choose the area where he wants that advisor to stand. He may not choose the advisor's home area, but may chose any other area, including the area where the advisor is standing (he need not move the advisor). An advisor may only be moved at the moment a player wins an election in the advisor's home district.
Elections in the districts
The winner of the election takes control of the district's advisor and stands it in the area of his choice (not its home district). If he abstains, he neutralizes the advisor and moves 1 house to or from this district. He then may place 2 houses from his supply in this district.
Whenever a player places or moves a house into a district, he immediately checks to see if he may build a palace there. Players may not build palaces in a district at any other time.
It has to be this way, otherwise what you describe is easily possible. Realize this though... this is only an issue if the district didn't have any houses to begin with. Otherwise, the tactic is perfectly legal. Also remember that the victory isn't checked until the end of the 'game year' (after all 7 districts have voted). So it may be possible for someone else to complete their win conditions as well by the end of the 'game year'.