Table: race_stats_30
Columns: year
rider
country
distance
pacing
velodrome

Question: What country had a winner in 1907?
SQL: SELECT "country" FROM race_stats_30 WHERE "year" = 1907

Question: What velodrome took place earlier than 1950 with a winner from France in tandem paced over a distance of 951.750 km?
SQL: SELECT "velodrome" FROM race_stats_30 WHERE "year" < 1950 AND "country" = 'france' AND "pacing" = 'tandem paced' AND "distance" = '951.750 km'