Having a lot of experience as a leader of several IT teams I would say that the key traits are responsibility and a strong will to discover how things work.

Why do I put responsibility on top? Because such person will be working with your data, may be with critical or confidential data, and you should be really sure that you can trust in him/her. Moreover, you must rely on him/her that his/her output is right, without any mistakes. Often you do not have any ways how to check such outputs.

Secondly, it is a will to discover. According to me you need a person that widens his/her eyes whenever you come with a problem. Such people are happy to dive into the problem and come up with an analysis and a solution. You need a motivated person that will be thinking about the data trying to get much as possible from it.

Hope I clearly understood your need. :-)