I don't want to confuse you with a lot of talk about ohms law and electrical stuff, so I'll get right to the point. You have an 11 watt panel that I assume is rated for 12 volts. This tells me that the current flow from the panel to the charge controller will not exceed 1 amp. To be on the safe side, the wire that you use from the panel to the charge controller should be no smaller than 18 guage. 18 guage wire can handle 2.3 amps, maximum. Your single LED light draws much less than 1 amp, so you can also use 18 guage wire from the battery to the light. However, it is important to point out that your battery is capable of putting out much more than 2.3 amps. A short circuit could cause 18 guage wire to catch fire. To avoid this, be sure to use fuses. For your application, you could use automotive fuses and fuse holders. Be sure to install a fuse at one of the battery terminals. Connect nothing else to this battery terminal. In doing so, you are making sure that a short circuit anywhere in your wiring will not result in a fire.
The length of the wire is also an important consideration. Wire has resistance, and you might need thicker wire to keep your voltage drop across that resistance to a minimum. Here is a web page that might be helpful:
http://www.powerstream.com/Wire_Size.htmJohn