Conversation so far:
When did the deposition happen ?
On 13 September, the Parliament held a joint session between the Senate and the Assembly.
What was the joint session about ?
Though several members short of a quorum, they voted to grant Lumumba emergency powers.
Why did gave him emergency powers ?
Parliament did not back Lumumba's dismissal of Kasa-Vubu, creating a constitutional crisis.

Question: How long did the emergency powers lasted ?
Self-contained rewrite: How long did the 13 September emergency powers given to Patrice Lumumba by Parliament last?