Teacher:In this task, you're given a context, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both context and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the context or linked information.
Teacher: Now, understand the problem? Solve this instance: Context: Blachstein was also affected more directly by the intense political tensions radiating out from Moscow, based on Stalin's suspicions - not entirely unfounded - that there might be comrades in the Soviet Union and further west in Europe who favoured an alternative Soviet leader. Link Information: Lenin died in January 1924. Stalin took charge Answer: 13
Student:
How long had Stalin been the leader of the Soviet Union by the year 1937?