Yes, both houses constitute Congress, but House Members are known as “Congressman” or Representative So-and-so, whereas Senators are called such. President Lincoln was the last House Member with no other experience elected to that high office.
And we've had about 4 presidents in 150 years since that have been worthwhile. So your point is?
Kennedy represented Massachusetts's 11th congressional district in the U.S. House of Representatives from 1947 to 1953 as a Democrat, and served in the U.S. Senate from 1953 until 1960
‘President Lincoln was the last House Member with no other experience elected to that high office.’
Actually Lincoln left the House in 1848, and was definitely a former Congressman by 1860. The one and only Congressman directly elected President was James Garfield.