You may still apply to be an HA if you have received an AOD violation, but you should be prepared to talk about your violation. When speaking to an interviewer, you should be able to explain what you learned, how you've changed your behavior, and how the experience might help you in the future.
One of the qualifications for being a House Advisor is to, "be in good disciplinary standing in accordance with Reed College policies and the Honor Principle. Applicants may not be eligible for the HA position if they have received two or more AOD violations at Reed."
If you have received multiple violations or a serious AOD violation, your application may not be considered.