previous council (elected before the incumbent) is what I actually need (please have a look at my first post in this discussion)... we only use "созыв" in this sense. those monthly meetings of the councill we call "сессия"
My sense is that the correct translation is 'session,' but you need to include the modifier, городской совет предыдущего (which session, in other words), i.e., previous city council session. I didn't offer all that in my translation as only созыв is highlighted in the question.
cf. "previous congressional session" or "previous session of Congress"
If there's a new "созыв" every month, though, probably the membership of the council remains the same. If you say "the previous council", it implies, as Alisa noted, that there has been an election and now there is a new council.
I think you could probably manage it by writing "the previous council session." Or, if you made it "last month's council session" then there would be less danger of somebody thinking it meant a session in the sense of a meeting on one day or one morning. The reason I don't like "convocation," is that it sounds like it means only the opening day.
Thank you very much indeed, Rachel. The council I'm writing about holds sessions every month and each session has its number. So I believe that "previous council" would be the most appropriate here...
In the USA, "session" can be used in exactly the sense that созыв has here. For example: "January 6, 2009. The 111th Session of the U.S. Congress began." You see? - There's been one session, every two years since 1789. But it doesn't always mean that, even for the U.S. Congress. Sometimes, the work-period which began Jan. 6, 2009 could be called "The 111th Congress, 1st Session", with the "2nd Session" being the one in 2010, until the 112th Congress will be sworn in, in January 2011.
Another problem is that this usage of "session" is not very widespread, beyond the particular institution of the U.S. Congress. So if you use it for other institutions, it can easily be mixed up with "the session we held today." Wherever possible, I used to try to translate "седьмого созыва", "предыдущего созыва" without "session", "convocation", etc. - see Alisa's entry.