CREATE TABLE table_201_25 (id NUMBER, "party" CLOB, "leader" CLOB, "from" CLOB, "to" CLOB)

which party had only one leader and only a three year office term ?
SELECT "party" FROM table_201_25 GROUP BY "party" HAVING COUNT("leader") = 1 AND "to" - "from" = 3
SELECT "party" FROM "table_201_25" GROUP BY "party" HAVING "to" - "from" = 3 AND COUNT("leader") = 1