I have a table like this:
A B C D E F G H I 10 23998 16755 27656 17659 19708 20328 19377 18925 20 37298 33368 53936 41421 44548 40756 40985 37294
I checked the documentation and I don't see a way to do it automatically, but you can manually set a title with
plot "file.txt" using 1:2 title "A" with lines smooth bezier ...