According to the EU novel The Never-Ending Sacrifice, the Detapa Council was, by and large, executed. One of their number survived (briefly) but was killed in the genocide committed by the Dominion against Cardassia Prime at the end of the Dominion War.
A third before the first bell, when it was still dark, the [council] building was stormed by the Jem’Hadar. They marched in, seized the Chief Executor and the Chief Archon, dragged them out and executed them on the spot. The images played on every channel for weeks afterward, in between repeat showings of Gul Dukat’s accession speech.
A civilian militia was created—a fifth of the strength of the previous
police force and directly answerable to Dukat—but the Jem’Hadar took
over maintenance of law and order in all urban centers. The rest of
the Detapa Council was tried and executed for “weakening the
Cardassian state.” Some high-ranking Assembly members shared this
fate; others were interned in labor camps or placed under house
arrest. As for the rest of the Five: Erek Rhemet, who had been
offworld at the time, was rumored to have sought asylum in Mathenite
space, joining Tekeny Ghemor to form a government-in-exile.