senator vs stand-in

senator

noun
  • A member of the ruler’s council or governing council in general, a leading statesman. 

  • A member, normally elected, in the house or chamber of a legislature called a senate, as, for instance, the legislatures of the United States and Canada. 

  • A member of the ancient Roman Senate. 

  • A member of a governing council in other states in the ancient world. 

stand-in

noun
  • A person of similar size and shape to an actor who "stands in" for that actor during the lengthy process of setting up a shot, but who, unlike a double, does not appear in the film. 

  • A substitute. 

How often have the words senator and stand-in occurred in a corpus of books? (source: Google Ngram Viewer )