Neither is correct.
The correct is “αυτά λέγονταν” or “αυτά λεγόντουσαν” (Παρατατικός τρίτο πληθυντικό, Past continuous third plural).
The form “λεγόταν” is third singular of past continuous. For example: “αυτό λεγόταν χθες”.
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Vasiliki Baskou, Instructor/Director, https://learn-greek-online.com.