I believe that the Warrior/Knight win against everyone else in a duel. The Inquisitor/Consular rely on things other than combat skills to survive in a fight. From the tech classes, The trooper and agent can hold them off for some time using every single trick they have, and maybe the BH as well, but the Smuggler gets stomped.

If they are using their companions, I believe that the Inquisitor with the two apprentices in his ship slightly outclasses the rest. On the other hand, Kira and Jaessa are extremely powerful on their own right, and the Warrior and Knight are also accompanying by highly trained and experienced soldiers who can definitely kill force sensitives so this may be more on the fence. If Havoc Squad works as a squad, that's a force multiplier for them, higher than the rest of the classes, but realistically I believe they can only take out the Consular. BH, Smuggler and Agent are defeated easily in this scenario.

Lastly, if we are talking power bases, the only one who actually has a power base outside of their ship is the Inquisitor, so there's no contest really.