Direct Assault does something instead of the normal claim effect
If you are the defender the claim affect is normally nothing - but does anything prevent you from taking a location instead of doing nothing?
Yes. When the defender wins a challenge, the "Challenge result is implemented" framework event does not initiate successfully (because its play restrictions - requiring the attacker to win - are not met). Replacement effects, like Direct Assault, are applied when the effect resolves, not when it initiates.
So, since "defender wins" means the "normal claim" never initiates, there is no "normal claim" to replace with the taking the location during resolution.
If you are the defending player and you play Direct Assault on the attacking character and still manage to win the challenge, you still don't get "claim" for winning on defense. You only lower the amount you would win/they lose the challenge by.
If Doran is in play, then the losing attacker also pays a claim affect - but I would say that Direct Assault is only replacing the "normal" claim effects - so would guess that you can take a location and the attacker still has to pay the claim effect triggered by Doran
Um… there is no "also" with Doran. What Doran does is change the play restrictions so that the "challenge result is implemented" framework event does
successfully initiate when a challenge is won on defense, defining such a challenge's "normal claim" as the standard challenge claim for that challenge type, just with the attacker in the role of "loser" and the defender in the role of "winner." So, since claim does
initiate, what would be "normal" for that challenge is replaced with what is written on Direct Assault.
So, if you are the defending player and you play Direct Assault on the attacking character and still manage to win the challenge while Doran is in play, you would get to steal a location from the attacker. (But that's it.)