You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Ann_Arbor,_Michigan

Context:
Ann Arbor is part of Michigan's 12th congressional district, represented in Congress by Representative Debbie Dingell, a Democrat. On the state level, the city is part of the 18th district in the Michigan Senate, represented by Democrat Rebekah Warren. In the Michigan House of Representatives, representation is split between the 55th district (northern Ann Arbor, part of Ann Arbor Township, and other surrounding areas, represented by Democrat Adam Zemke), the 53rd district (most of downtown and the southern half of the city, represented by Democrat Jeff Irwin) and the 52nd district (southwestern areas outside Ann Arbor proper and western Washtenaw County, represented by Democrat Gretchen Driskell).

Question:
On a state level the city is part of which district number?

18th district