>Haskell has no null definition of type Char, at least according to this Stack Overflow answer. Python doesn't distinguish between Char and String types with single and double quotes, so empty char is empty string is an empty list. It seems weird to me that for all the typing wealth Haskell provides, this base case doesn't exist, though I personally don't know what it is.
An empty string is equivalent to an empty list []
If you want a null use the maybe monad.