If the lease is in compliance with state laws (some state bar long automatic extensions) then the provision for extension could apply. It would be incumbent on both YOU and the landlord to comply with the notice requirement.
For the ND statutes (PDF Format):
http://ranch.state.nd.us/LR/01/cencode/CCT47.pdf
Did the landlord give you specific notice of the renewal as required in 47-16-06.1 (below)???
"47-16-06. When a lease is presumed renewed. If a lessee of real property remains in possession thereof after the expiration of the hiring and the lessor accepts rent from the lessee, the parties are presumed to have renewed the hiring on the same terms and for the same time, not exceeding one year.
47-16-06.1. Automatic renewal of leases of residential real property - When notice
required. Notwithstanding the provisions of section 47-16-06, in any lease of a specified term of two months or more of real property used for residential purposes, the lessor may not enforce an automatic renewal clause of a lease unless the lessor has notified the lessee in writing, delivered personally or by first-class mail, of the automatic renewal provision, not less than thirty days prior to the expiration date of the current lease. If such notice has not been given, the lease expires, and the terms of the latest lease convert to a month-to-month tenancy."