Which crytocurrency was ranked the first by CoinMarketCap on 2013/4/28?
ranked the first refers to cmc_rank = 1; on 2013/4/28 refers to date = '2013-04-28'
SELECT T1.name FROM coins AS T1 INNER JOIN historical AS T2 ON T1.id = T2.coin_id WHERE T2.date = '2013-04-28' AND T2.cmc_rank = 1