Thanks for the info! Sitcoms are typically not my kind of show, but I occasionally watched episodes of a few when growing up (such as Growing Pains & Facts of Life).
In the U.S. for a full season, usually 22-24 episodes is standard for original network (CBS, NBC & ABC) shows, including sitcoms. However, sometimes if shows premiere later in a season they will have less episodes.
DOH premiered about halfway through that TV season (January 1979), so Season 1 only had 13 episodes.
Nowadays though, cable network & streaming shows usually have only around 10-13 episodes a season.
Rick should have stayed on DOH.