Can't find the right drill bit--please help

Thanks, guys for all the suggestions. I finally got the roll pin out after heating up the shaft and using some masonry drill bits. I had to go through 4 bits but along with the heat I was finally able to drill out approximately half then punch out the remaining roll pin. Can't believe how hard this was to drill. Again, thanks for all the ideas. I'm glad I can turn to this forum when I need help.