CREATE TABLE table_25275 ("Constituency" TEXT, "Winner" TEXT, "Party" TEXT, "Margin" FLOAT, "Runner-up a" TEXT, "Party a" TEXT)

Name the most margin for nco party and p. ramachandran won
SELECT MAX("Margin") FROM table_25275 WHERE "Party" = 'NCO' AND "Winner" = 'P. Ramachandran'
SELECT MAX("Margin") FROM "table_25275" WHERE "Party" = 'NCO' AND "Winner" = 'P. Ramachandran'