This might help.

1) You can have a hardware set up that will sync your 303 to logic using midi (see manual for "sync"). Then, program your beats into the 303's internal sequencer, and when you hit start on Logic, the 303 will play along in time (sync). Then, while the 303 is playing along, you can record the beats into logic. After that you can then sequence the recorded audio file.

2) You can have a hardware set up that will send midi data from logic into the 303. The midi data coming from Logic will trigger beats that are inside the 303. While logic is running, then, the beats being played back by the 303 can be recorded back into logic, and the recorded audio file can later be sequenced. If you like this option see 3.

3) If you have another midi port for your computer, plug in your Oxygen 8 and in the Logic Arrange Page highlight the midi track that coressponds to the 303. Now, when logic is not running, you should still be able to play notes on th Oxygen 8 and hear the beats being triggered in the 303 as a result of the midi data sent from Oxy8 via logic to the 303. From here:

a) Hit record in Logic, and record your midi data (played from Oxy8)
b) Playback your newly recorded midi (that is now triggering the 303)
c) Record the audio playing out of the 303 back into Logic and after, you can squence the recorded audio file.