I think you have a bigger problem than what you are working on. What happens if you get an entry in table 2 of "1,Young"? Do you still want Watson or would you now want Young? Also, how do you know your user wouldn't want the others. Typically, you'd want to keep a persons entire name in the same table rather than trying to join it up this way. Or if you were really out to save on disk space you could go with three tables, such as:
I forgot to mention in my earlier post. If you were going with the three table solution that I spoke of, I would suggest two unique indexes on the first and last name tables. One for the ID number as you DO NOT want to end up with what you have already(not knowing which name should be used). The other on the name itself, reason being you are attempting this solution, so as to not duplicate a name, so ensure that you do not duplicate it. Without those indexes on both tables you would just be setting yourself up for data errors down the road. If that were to happen, then Vincent McBurney or one of those other data quality people would be hunting you down.