since podcasts are I think just RSS feeds of audio files (mp3 for those I've checked) the ads aren't in any way marked in the stream. The only thing I've found is adjusting the skip buttons in antennapod so that skip fwd does 10 seconds, and back does 5; that seems to let me avoid listening to most of the ad; tap fwd until it's back in material, then back once.
But I listen to a lot less podcasts; if I want hands- and eyes-free material I'm more likely to use TTS in my (text) RSS feed reader of choice, currently Feeder.