No! Cyberduck is a FTP-Programm. You need the database credentials.
I guess you got a tool from your hosting provider to setup a database. Do you use Plesk? Something else?
However, to setup a database you need a database-user first, with name and password. For the initial setup of the database you have to name it. Example: S9Y. After the setup you can connect your database with phpMyAdmin, you will find your servername on top, in the first line. In my case there it says: Server: localhost:3306 <- only as an example!
Now you have all 4 values you need to configure Serendipity:
- Database Servername = localhost:3306
- Database User = name
- Database Password= password
- Database Name = S9Y
Good luck!