CREATE TABLE table_75315 ("Date" TEXT, "Type" TEXT, "Record description" TEXT, "Achievement" TEXT, "Pilot" TEXT)

Date of 23 september 1961, and a Pilot of b.v. zemskov had what record description?
SELECT "Record description" FROM table_75315 WHERE "Date" = '23 september 1961' AND "Pilot" = 'b.v. zemskov'
SELECT "Record description" FROM "table_75315" WHERE "Date" = '23 september 1961' AND "Pilot" = 'b.v. zemskov'