Actually the 45th Congress began in 1877-79 and the person to hold the Speaker title was the 29th (Samuel J. Randall) person. The 44th congress was in 1875-87. Mike Johnson is the 56th person to hold the title and he's Speaker of the 118th congress. It's quite confusing, but you can fact check me by looking at the Speaker list (link included). Steve Scalise did in fact introduce Johnson as the 45th speaker, but the other facts don't quite match up, still note worthy tho. The 45th person (John W. McCormack) to be Speaker began in 1962 and was Speaker of the 87th-91st Congress
https://history.house.gov/People/Office/Speakers_Numerical_Order/