Do you usually have the other options? iTunes does not offer all it's content in all countries. It may be necessary to get an account in another country to get access to the other store areas. The usual choice is the U.S, but the U.K. can be a better choice, depending on what you're after.
If you know your iTunes account and country have the other content, try these fixes and see what happens.
Scroll to the bottom of the Podcast tab and make sure you are logged in with your Apple ID. Try signing out and back in by tapping on it.
Close/Clear the app: With the problem app closed, double tap on the Home button to get the multitask bar. Tap and hold on any icon in the bar until they jiggle, then tap the minus sign on the problem app. This will remove it from RAM and insure a clean start the next time you launch the app.
If that does not work try a restart,
Restart: Hold down the power button until the power off slider appears. Slide it off. When the iPad finishes shutting down, hold down the power button again until the Apple logo appears. Apple recommends you restart the iPad at least once a month.
and then a reset if that does not work.
Reset: Hold down the power and home buttons until the Apple logo appears. The iPad will reboot. This usually takes a bit longer than a restart.