Question: Robert Nelson Cornelius Nix Sr., was an American politician who served in the United States House of Representatives from 1958 until 1979, he was the first African American to represent Pennsylvania in the House of Representatives, the first African Americans to serve in the United States Congress were Republicans, elected during which time period?
Sentence (from "Robert N. C. Nix Sr."): He was the first African American to represent Pennsylvania in the House of Representatives.
Relevant evidence: Yes