Ngige still a Senator?

I having been thinking about this issue since the gubernatorial election in Anambra lingers. Is Ngige still a senator? Didn't he resign his seat in the senate to allow him contest for the election?
I think he must have resigned; if so, when is election holding in his constituency to replace the vacancy?
If soon, is he still eligible to contest? If yes, will he still contest under APC?
Will APC contest future election with this massive rejection of the party by Anambarians, though they filled a credible candidate in Ngige? Is APC Ngige's political waterloo in Anambra, SE and entire Nigeria?

Just asking because I thought for any civil or public officer to contest for another office he must resign his present position.

Why should he resign?? Did Seriaki Dickson resign when he was contesting for Bayelsa Governorship election??