Answer:incumbent:the holder of an office or post.
challenger:a person who engages in a contest.
liberal: (in a political context) favoring maximum individual liberty in political and social reform.
conservative: holding to traditional attitudes and values and cautious about change or innovation, typically in relation to politics or religion.
moderate:average in amount, intensity, quality, or degree.
front-runner: the contestant that is leading in a race or other competition.
dark horse:a candidate or competitor about whom little is known but who unexpectedly wins or succeeds.
