Ok, I've found the file. It's the blue.tga file in gfx.
It has the following numbers: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 and 30. I wanted to make numbers for 1980 season, so I removed 0 13 19 and 24 and put in 31 41 43 and 50 and moved all the numbers so 1 came to the spot of original 0, 2 to the spot of original 1 and so on the last number(50) coming to the spot of last original number(30).
But when I started the game, everything was wrong and upside down.
I first converted tga into bitmap, edited it, then converted it back to tga and put in the game, but it all got corrupted. Any ideas where did it all go wrong?