Darth Bane (orbalisk) vs Darth Maul (TPM)

Standard

Bane

Bane

Maul

Bane. Maul doesn't have Force lightning to bypass the defense of the orbalisks, and Bane has very few openings in his orbalisk armor that Maul could target. Not to mention how skilled and powerful Bane is in his own right.

Bane. Maul isn't diverse enough in skillset to deal with Orbalisks in a way that Bane can't just counter, and he isn't overpowering Bane physically either

Two outcomes 

Bane wins

Bane downscaling is so yuge, Maul stabs him in the mouth faster than thought