It must be the power of the deputy district chief, because you are comparing power rather than rank, and the power can only be compared in the same place. The mayor of Shanghai is in the main hall, and the mayor of Qingyuan is in the main hall. There is a big gap between the administrative levels of the Party committee and the government. Compare this example: a director in a national Ministry, who is in charge of those offices in the Ministry. Compared with the vice mayor of a prefecture-level city, it is indeed half a level higher, but it may manage the construction, education and medical care of the city.