The emerging consensus within the tri-party alliance was to allocate the chief minister’s post to Shiv Sena, speaker’s to Congress and deputy chief minister’s to NCP. Thus, Uddhav Thackeray was installed CM, but Congress has now taken the view that it is not keen to nominate the speaker and would rather prefer a deputy CM’s post.

from Times of India https://timesofindia.indiatimes.com/city/mumbai/speaker-likely-from-congress-but-no-clarity-on-second-deputy-cm-post/articleshow/72302629.cms