English: “It shall be the first for you of the months of the year” — that Nisan should be the head for counting the months, but for years Tishrei is the head.
On the daf / in context: See the cited source for the full section.
Type of Learning
Derash on the verse (midrash / halachic) — not a formal named middah of the 13.
What Is Learned
Nisan is the first month for the festival calendar; Tishrei remains the head for years.