How do I say in a polite way "if this position is temporary, I'm not interested"?

Working in schools. I got an offer for next school year at a place that seems well enough in a role I want to work in, but amidst all the applications I'd been sending out, I missed that this position says "August through November." It doesn't mention anywhere about the job being a substitute position, nor necessarily that it's temporary, but I've been unable to find additional info. I also have yet to receive another offer elsewhere. The main reason I'm curious is that the website I was directed to was one I've used for substitute jobs in the past and that, as far as I'm aware, is mainly designed for substitutes.

The main question I wanna get across is "is the plan to decide if you're renewing in November, or once November comes around am I for sure gone and this is just a temporary position? Cause if it's not something long term I'm not interested anymore / I want to keep my options open for a more long term offer." Not sure how to word that in a way that says I'm still interested, but will take a better offer. I've not signed any contracts yet but said I'd be interested in the job.