Use a length of kitchen paper towel that is long enough to go across the rim of the pot. Fold it like a fan, lay it across the rim and put the lid on. This will also act like a wick and will draw any moisture out of the oven.
This is necessary because without a good air supply, the oil that you used to season it may turn rancid. If your pot goes rancid, you mustn’t cook in it and will have to clean it and re-season it.