actually, you are introducing a useless column there by having both an "independant" and "party" column. being "independant" can be considering being part of a "party" - the independant party.

those are mutually exclusive properties. it's the same as saying a candidate cannot be in two different parties at the same time.

i would personally model that one as a lookup value - a foreign key to a list of parties a candidate can belong to, listing independant as one of the possible parties.

in other words "party" and "indepedent" are the same attribute so should be the same column.