Hinduism does not have a supreme god...shiv, Vishnu all r part of mythology...the Creation Hymn of the Rig Veda, (one of the oldest spiritual books of the Hindus), talks abet a 'single primordial and extremely abstract principle designated as THAT, from which the entire world evolved.this principal is pure consciousness or pure spirit.
read the essentials of Hinduism to really understand the religion
Supreme - is Parabhramam. God is unique in Hinduism, you are asking a question like which part of our body is supreme. No its not like that. They are the path to the supreme - ParaBhramam., either you follow Shaivam or you follow vanadium.
As per Hinduism, there is one eternal Supreme Consciousness who is named as Bramh or Aum or Turiya. some also name this supreme Consciousness as Krishna or ParamShiva.
This supreme consciousness manifests as a Trinity of gods viz. Brahmaa (for creation), Vishnu (as preserver) and Shiva (for destruction)...and they are all equal manifestations..no bigger no smaller.
it depends on u how u see each one but u k know GOD is only and only one if u r having any query so fine all answer here
http://www.soothsayers-india.com
Both are one at the same. 2 sides of same coin. The supreme is permanent Consciousness and blissful state. When this is in static form it is called as Vishnu represented/depicted in the form of Lord Ranganatha in lying posture on a serpent in deep meditation. In moving form as Lord Nataraja in dancing posture with constant vibration. This just like the same person in deep sleep state and awakening state. O.K.