You could be correct, I could be correct, or both. The rule is somewhat ambiguous:
https://www.archives.gov/federal-register/electoral-college/key-dates.html
Quote from link:
“If no Presidential candidate wins 270 or more electoral votes, a majority, the 12th Amendment to the Constitution provides for the House of Representatives to decide the Presidential election. If necessary the House would elect the President by majority vote, choosing from the three candidates who received the greatest number of electoral votes. The vote would be taken by state, with each state having one vote.”
If I understand correctly, then easy state member of the house would vote by state. So the question would be how many states have more dem members than republicans?