CREATE TABLE table_29237 ("City" TEXT, "Population" FLOAT, "Registered voters" TEXT, "Democratic" TEXT, "Republican" TEXT, "D\\u2013R spread" TEXT, "Other" TEXT, "No party preference" TEXT)

what is the percentage of democratic voters in which the registered voters is 67.8%?
SELECT "Democratic" FROM table_29237 WHERE "Registered voters" = '67.8%'
SELECT "Democratic" FROM "table_29237" WHERE "Registered voters" = '67.8%'