Okay, because of all the samples people provided me with I began trying even more combinations and finally learned that if I uppercase the NAME attribute, then it works. What?
Here's the zen code which actually works:
input[type="text" NAME="demo"]
or
input[type="text"][NAME="demo"]
Finally, I even tried UPPERCASING one letter in name like (notice uppercase 'A'):
input[type="text"][nAme="demo"]
All these result in:
Crazy. Mark this down as a bug. :)