I just checked a podcast, then closed and reopened iTunes 11.0.1 and it did open where I left off.
First thing you should do is click "Get Info" on the Podcast (command "i"), then click the "options" tab.
Then look to make sure "Remember Playback Position" is checked. If it's not, that will be the cause of iTunes not remembering the position.
I was unaware of the "Get Info" trick, so that was helpful to know. But it doesn't get to the heart of my question. Pre - iTunes 11, if I paused an episode of a podcast and closed iTunes, then the next time I opened iTunes that same episode was cued up and showed at the top of the window when I pressed play. Now, when I pause an episode of a podcast in iTunes 11 and close it and then re-open iTunes, it takes me to the main page for podcasts. Since I have a long list of podcasts and a number of episodes under each one, it can take some time to browse through my list of podcast to find the episode I was listening to. When I finally do find it, select it and press play, it resumes where I left off. But I had to find it first. Often several days will go by between listening sessions and it can take forever to remember where I left off and where to find it. If I open iTunes 11 and simply press play, it begins with the first episode in the first podcast listed in the window, not where I last listened to iTunes.
I have no solution for that - but I get what you're saying.
What I would do, and I don't know if this would work for you, is create a playlist of podcasts, arrange them in the order you want to listen. I know you can drag podcasts into playlists like you would with any song, and iTunes will treat them like songs - you can sort them by date added or name. Stupid to have to workaround when it worked fine before, but this would quickly get you to the podcast you were listening to. The "resume playback from where you left off" function will still work if you do it this way.
This is another bullet point in the long list of what's wrong with iTune11. Today on a song I was trying to get to "show in finder", I accidentally let go on "show in iTunes store" instead. iTunes rocketed to the store, and there was no way for me to get back to what I had been looking at before - it required conducting the same search all over again. I don't recall this being a problem in earlier versions of iTunes, you could go back.
Good luck !