CREATE TABLE table_25278 ("Constituency" TEXT, "Winner" TEXT, "Party" TEXT, "Margin" FLOAT, "Runner-up a" TEXT, "Party a" TEXT)

Name the total number of runner up a for perambalur
SELECT COUNT("Runner-up a") FROM table_25278 WHERE "Constituency" = 'Perambalur'
SELECT COUNT("Runner-up a") FROM "table_25278" WHERE "Constituency" = 'Perambalur'