Possible solution or what to say, when you get called on to say something in a meeting but you have nothing to say?

This happens a lot and I struggle as I can either spend the entire thinking of something to say or actively listening to people.

Usually I get called on eventually because I don’t say anything. Is something along the lines of “I’m still thinking about it.” (Obviously worded a bit nicer) Appropriate?

Or you just have to come up with something then and there? Cause I’m terrible of thinking of what to say on the spot like that