What happens to the role of Mayor after the state election?

If the Mayor is an unsuccessful candidate, they resume the office of Mayor.

If the Mayor is the successful candidate, then a casual vacancy in the office of Mayor occurs. No supplementary election for Mayor is required, but the Council will need to elect by resolution who is the acting mayor for the remainder of the term.  It is not assumed that it will be the Deputy Mayor.

Local Government Act 1999 sections 51(10) and sections 54(8).