Cable to use for recording iPad

I am using Logic Pro 10.1.1 with an external USB interface that has eight 1/4" / XLR combo inputs. I am trying to use one of them to record audio off of my iPad. When listening to the input I don't get the entire all the audio in Logic. If I jiggle the connection to the iPad an pull it out a little I can get all the audio... Obviously not good for recording. What kind of cable do I need to do this correctly? I want the input to be stereo.

Thanks