I haven't read them in awhile, but my recollection is that in the Terok Nor trilogy of novels, if Dukat isn't the only prefect of Bajor, he's one of only two, and the first one is the one who ultimately leaves the delightful message for him in "Civil Defense". I'm not saying that's how it must be, or even that that's the most probable chain of events...on the other hand, I've been working for the same company for almost 20 years now with minimal changes in my role, so it's not out of the realm of probability, especially considering that Dukat seemed to relish being prefect.