CREATE TABLE table_18807 ("Rank by average" FLOAT, "Competition finish" FLOAT, "Couple" CLOB, "Total" FLOAT, "Number of dances" FLOAT, "Average" CLOB)

tell the competitions where the mean is 1
SELECT "Average" FROM table_18807 WHERE "Number of dances" = '1'
SELECT "Average" FROM "table_18807" WHERE "Number of dances" = '1'