If you want to clear the space from the phone, you can make up space by deleting the individual episodes from podcasts. By navigating to settings, going to general and then iPhone storage, you can check current storage. You can check the storage that your podcast is consuming by checking over there.
By navigating to library, then shows and selecting the show, you can delete the individual episodes. Scroll through all listed episodes and search that you want to delete. The shows that don’t have an iCloud icon are actually stored in the device and you can delete them easily. If you will remove these episodes, you can easily free up the space.
Delete a show from the library by simply tapping and holding down on the show that you want to delete. Tap remove icon and then click the trashcan icon that is shown in your podcast app.