I really don't think that is repairable by welding or brazing because there is not much there to work with. And like Wayward said, old cast iron is a bi--h to weld because of the heat "expansion" of the two different metals as they heat up & cool down. One does it faster than the other and the weld will "snap" back apart or cause a new break.
Tales, what I suggest is, iffen you really want to keep it, take it to someone, say a machine shop, and have them "drill it" and epoxy a steel dowel pin in it. The trick is to get the holes "centered and aligned" correctly and not just anyone can do that.
Do that and it will be stronger than the original and the break will not be noticable unless closely inspected.